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Reactive and Functional Polymers

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ISSN (Print) 1381-5148
Published by Elsevier

[2564 journals]

Special Issue in GElsympo2013, which was held in Tsukuba, Japan on September 10-12, 2012
- Abstract: Publication date: Available online 16 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Yukio Nagasaki
  
  PubDate: 2013-05-19T09:33:56Z
LCST Phase Separation and Thermoreversible Gelation in Aqueous Solutions of Stereo-Controlled Poly(N-isopropylacrylamide)s
- Abstract: Publication date: Available online 14 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Fumihiko Tanaka , Yukiteru Katsumoto , Shinya Nakano , Rio Kita
  Stereoregular poly(N-isopropylacrylamide)s with controlled content of isotactic dyads have recently been synthesized, and interesting interference phenomena between LCST phase separation and high-temperature reversible gelation have been observed in their aqueous solutions. We develop a model solution in which dehydrated stereo-regular isotactic segments on polymers are driven into intermolecular cross-links leading to gelation. We theoretically calculate the phase diagrams for the varied content isotactic dyads and compare with the experimental data.
  
  PubDate: 2013-05-19T09:33:56Z
A Metal-Sensitive Organic-Inorganic Hybrid Surfactant: POSS-Capped Dipicolinic Acid-Functionalized Poly(ethylene glycol) Amphiphile
- Abstract: Publication date: Available online 14 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Chen Lingnan , Zeng Birong , Xie Jianjie , Yu Shirong , Yuan Conghui , Pan Yinyin , Luo Weiang , Liu Xinyu , He Kaibin , Xu Yiting , Dai Lizong
  A novel metal responsive organic-inorganic hybrid amphiphile with a well-defined cage structure bearing a hydrophobic polyhedral oligomeric silsesquioxane (POSS) head and a hydrophilic poly(ethylene glycol) tail functionalized with a bidendate ligand was synthesized via amidation and esterification reactions. The structure of the novel amphiphilic surfactant, aminopropylisooctyl-POSS-maleic acid-poly-(ethylene glycol)-dipicolinic acid (POSS-MA-PEG-DPA), was characterized by NMR, and its self-assembly behavior was investigated by transmission electron microscopy, dynamic light scattering, and UV-visible spectrophotometry. The experimental results revealed that the micelle morphology could be controlled by the addition of zinc ions. The proposed modulation mechanism involves the combination of hydrophobicity, metal coordination and repulsive interactions. Furthermore, the coordination bonds provide the micelles with good dynamic and thermal stability. We also found that the tadpole-shaped amphiphile could form reverse micelles with an average diameter of approximately 30 nm.
  
  PubDate: 2013-05-19T09:33:56Z
Editors and Editorial Board
- Abstract: Publication date: June 2013
  Source:Reactive and Functional Polymers, Volume 73, Issue 6
  
  PubDate: 2013-05-15T09:35:58Z
A systemic gene vector constructed by zwitterionic polymer modified low molecular weight PEI
- Abstract: Publication date: Available online 9 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Wei Wang , Wenjing Nan , Liang Sun , Wenguang Liu
  Good blood compatibility and long-term circulation are very important to polycationic systemic gene vectors. In this work, polysulfobetaine-modified low molecular weight polyethyleneimine (LMW PEI, 1.8k) was synthesized and investigated as a vector for gene delivery in vitro and in vivo. PHEAA-b-PMPDSAH was synthesized via atomic transfer radical polymerization method, and then LMW PEI was grafted to PHEAA-b-PMPDSAH by an amido-hydroxy reaction. Incorporation of PMPDSAH into PEI was shown to retain the uncompromised ability to condense DNA into nanocomplexes. MTT assays revealed that the cytotoxicity of LMW PEI-PHEAA-b-PMPDSAH/DNA complexes was lower than that of PEI (25k)/DNA and LMW PEI-PHEAA/DNA complexes. LMW PEI-PHEAA-b-PMPDSAH50 was much superior to PEI (25k) in mediating gene transfection in the presence of 10% serum. At higher serum contents, the transfection of LMW PEI-PHEAA and PEI (25k) was deteriorated, whereas LMW PEI-PHEAA-b-PMPDSAH50 still retained better transfection efficiency, 8-fold more effective than PEI (25k). The expression of red fluorescence protein (RFP) was evaluated by small animal in vivo fluorescence imaging system and the results showed that the expression of RFP was much higher in the mice injected with LMW PEI-PHEAA-b-PMPDSAH50/pDNA-RFP than with LMW PEI-HEAA/pDNA-RFP. Both in vitro and in vivo results suggested that LMW PEI-PHEAA-b-PMPDSAHX copolymer holds a great potential as a vector for systemic gene therapy.
  
  PubDate: 2013-05-11T09:36:28Z
Development of a new azido-oxazoline monomer for the preparation of amphiphilic graft copolymers by combination of cationic ring-opening polymerization and click chemistry
- Abstract: Publication date: Available online 9 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Thanh-Xuan Lav , Pierre Lemechko , Estelle Renard , Catherine Amiel , Valérie Langlois , Gisèle Volet
  A new monomer (2-(5-azidopentyl)-2-oxazoline) bearing an azido group was synthesized. The cationic ring-opening copolymerization of this monomer with 2-methyl-2-oxazoline resulted in a well-defined linear polymer backbone with pendant azido groups. Alkynyl-poly(d,l-lactide) was grafted onto the azido groups of poly(oxazoline) via a Huisgen 1,3-dipolar cycloaddition reaction to give a novel amphiphilic graft copolymer [poly(2-methyl-2-oxazoline-co-2-pentyl-2-oxazoline)-g-poly(d,l-lactide)] (P[(MeOx-co-PentOx)-g-LA]). Different graft copolymers were prepared with PLA of different lengths. Preliminary results of the self-association of this copolymer in water indicated the formation of nanoparticles, which suggests this copolymer may have applications as vehicles for drug delivery.
  
  PubDate: 2013-05-11T09:36:28Z
Stabilization of oxidable vitamins by flavonoid-based hydrogels
- Abstract: Publication date: Available online 9 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Umile Gianfranco Spizzirri , Giuseppe Cirillo , Manuela Curcio , Ilaria Altimari , Nevio Picci , Francesca Iemma
  This study has the goal to evaluate thestabilityof B complex vitamins, loaded into catechin-based crosslinked hydrogels, in aqueous medium at accelerated conditions of oxidative stress. The formulations were prepared by coupling polyacrylic acid with catechin in the presence of dicycloexylcarbodiimide. Folic acid (FA) and Thiamine (TH) were chosen within the B complex vitamins because of the well-known oxidative degradation characteristics. The protective role of the hydrogels against the oxidation damage was monitored inducing oxidative stress, by means of UV irradiation and t-butyl hydroperoxide treatment for FA and TH, respectively. The characterization of the hydrogels was obtained by morphological, calorimetric, FT-IR analyses, antioxidant assays and evaluation of the swelling behaviour in aqueous media at different pH. The experimental results confirmed the suitability of the hydrogels as pH-responsive devices, furthermore the presence of oxidative condition proved the protective effect of the hydrogels. Catechin-based polymers gave a pronounced improvement in the stability of vitamins compared to hydrogels prepared by the coupling reaction of polyacrylic acid in the presence of 1,6-hexandiol. Under oxidative conditions, FA and TH were preserved by 96 and 60% respectively.
  
  PubDate: 2013-05-11T09:36:28Z
Silylated montmorillonite based molecularly imprinted polymer for the selective binding and controlled release of thiamine hydrochloride
- Abstract: Publication date: Available online 9 May 2013
  Source:Reactive and Functional Polymers
  Author(s): T.S. Anirudhan , P.L. Divya , J. Nima
  In the present study, specific binding and controlled release of thiamine hydrochloride (THC) to and from a novel molecularly imprinted polymer matrix namely, THC-templated-silylated montmorillonite-itaconic acid polymer (MIP) was investigated. The polymer matrix was characterized by means of XRD, FTIR and SEM analyses. Optimization of various imprinting components and binding characteristics of THC by the novel MIP were examined in detail. The binding affinity of THC for MIP was found to be greater than that for non-imprinted polymer (NIP). The maximum binding was found to be at solution pH of 4.5. The Sips isotherm model was found to describe well the equilibrium binding data with maximum binding capacity of 100 mg/g for MIP. The kinetic study revealed that the binding of THC onto MIP follows pseudo-second-order kinetic model with correlation coefficient 0.999. The swelling study of MIP in distilled water showed that the maximum swelling capacity is 329.0 g/g at about 8 h. In vitro release experiments showed that MIP releases drug in intestinal fluid with a controlled manner. The release kinetics of drug from MIP was analyzed using Ritger-Peppas model. The binding specificity of MIP for THC was tested using different substrates having structural analogue to the template, THC.
  Graphical abstract
  
  PubDate: 2013-05-11T09:36:28Z
Nucleation as a new Concept for Morphology Adjustment of Crystalline Thermosetting Epoxy Polymers
- Abstract: Publication date: Available online 7 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Hendrik Lützen , Thorsten M. Gesing , Andreas Hartwig
  Partially crystalline thermosetting epoxy polymers of defined heterogeneous morphology are herein presented. Crystalline poly(ε-caprolactone) (PCL) domains are covalently integrated into the cationically polymerized epoxy network. Although crystallinity is common in thermoplastic polymers, these new materials are among the first examples of partially crystalline thermosetting polymers. Nucleation is crucial and leads to a defined heterogeneous morphology. Homogeneous and heterogeneous polymers with identical composition can be prepared by initiation below or above the melting point of the PCL, respectively. While the homogeneous polymer showed the expected decrease in crosslinking density of the epoxy network and low glass transition temperature (Tg), the epoxy phase is not substantially influenced in the case of the heterogeneous morphology, showing two separated modulus changes at the melting point of PCL and the Tg of the epoxy matrix polymer.
  
  PubDate: 2013-05-11T09:36:28Z
Bio-based thermosetting bismaleimide resins using eugenol, bieugenol and eugenol novolac
- Abstract: Publication date: Available online 10 May 2013
  Source:Reactive and Functional Polymers
  Author(s): Mitsuhiro Shibata , Naozumi Tetramoto , Ayumi Imada , Makiyo Neda , Shimon Sugimoto
  5,5’-Bieugenol (BEG) and eugenol novolac (EGN) were synthesized by the oxidative coupling reaction of eugenol (EG) and the addition-condensation reaction of EG with formaldehyde, respectively. The EG, BEG and EGN were prepolymerized with 4,4’-bismaleimidediphenylmethane (BMI) at 180 °C and then compression-molded at finally 250 °C for 6 h to produce cured EG/BMI (EB), BEG/BMI (BB) and EGN/BMI (NB) resins with eugenol/maleimide unit ratios of 1/1, 1/2 and 1/3. The FT-IR analysis of EBs and 13C-NMR analysis of the model reaction product of EG/N-phenylmaleimide (PMI) 1/3 at 200 °C for 12 h suggested that the ene reaction and subsequent Diels-Alder/ene reactions mainly occurred for EBs. The FT-IR analyses of BBs and NBs supported the occurrence of ene reaction and subsequent thermal addition copolymerization in a similar manner to the well-known curing reaction of 2,2’-diallybisphenol A and BMI. The glass transition temperature (T g) and 5% weight loss temperature (T 5) of the cured resin increased with increasing BMI content, and EB 1/3 showed the highest T g 377 °C and T 5 475 °C. The flexural strengths and moduli of EBs and NBs were higher than those of BBs, and EB 1/2 showed the most balanced flexural strength and modulus (84.5 MPa and 2.75 GPa). The FE-SEM analysis revealed that there is no phase separation for all the cured resins.
  
  PubDate: 2013-05-11T09:36:28Z
Influence of the environment on swelling of hydrophilic polymers
- Abstract: Publication date: Available online 30 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Nikolai B. Ferapontov , Mikhail G. Tokmachev , Aleksander N. Gagarin , Nadezda L. Strusovskaya , Svetlana N. Khudyakova
  The influence of water activity on swelling of cross-linked hydrophilic polymers in electrolyte solutions of various concentrations was studied. A heterophase model was proposed to explain the polymer swelling. It was shown that the change in polymer swelling deals with different water sorption, and is described by water vapour sorption isotherm. At the same time, the volume of external solution taken up by polymer at swelling is constant and independent of concentration of the solution. Three models describing the structure of polymer gels were suggested and discussed on the base of the obtained results.
  
  PubDate: 2013-05-03T09:37:08Z
Preparation of quaternized poly(vinylidene fluoride) membranes by γ-ray irradiation induced graft polymerization and their antibacterial property
- Abstract: Publication date: Available online 30 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Qingyang Gu , Zhiqian Jia
  PVDF microfiltration membranes were modified by γ-ray irradiation induced grafting polymerization of 4-vinyl pyridine (4-VP) and then quaternization by n-butyl chloride. The effects of grafting method (simultaneous irradiation, pre-irradiation/UV), grafting conditions (absorbed dose, UV irradiation time, and 4-VP concentration) and quaternization conditions (temperature, time, and concentration of n-butyl chloride) were investigated. It was found that, the grafting degree initially increases with the absorbed dose and then reaches a plateau. The optimal concentration of 4-VP is around 15 wt%. The ion exchange capacity increases with quaternization temperature, time, and concentration of n-butyl chloride. After modification, the pores size, permeation flux, as well as elongation at break, of quaternized membrane decreases, while the retention coefficient, tensile strength and Young’s modulus increase apparently. Upon contacting with the membranes, the E. coli concentration decreases gradually. It is the adsorption mechanism for the pristine membranes whereas contact-killing mechanism for the quaternized membranes. Simultaneous irradiation is more effective than pre-irradiation/UV in the improvement of antibacterial property of membranes.
  
  PubDate: 2013-05-03T09:37:08Z
Examining structure property relationships in coatings based on substituted linear aromatic polycyanurates
- Abstract: Publication date: Available online 30 April 2013
  Source:Reactive and Functional Polymers
  Author(s): I. Hamerton , B.J. Howlin , D.A. Tilbrook
  Three series of halogenated and non-halogenated polycyanurates are prepared in good yield and purity, and fully characterised. Many of the resulting polymers, formed at room temperature using phase transfer catalysis, can be cast into films with good resilience and high thermal stability (some examples suffer no mass loss when held isothermally at 190°C and only display appreciable losses when held continuously at 300°C). Char yields of 35-65% are achieved in nitrogen depending on backbone structure. Some problems were encountered with solubility, particularly with heavily halogenated dichlorotriazines, which limited molecular weights (Mn = 2000-4000 g mol-1 depending on backbone structure) although when the phase volume ratio was altered to 0.25 higher molecular weights (Mn = 10000-30000 g mol-1) were possible. Best solubility was achieved by using aromatic diols with at least two equivalent phenylene units per dichlorotriazine unit. DSC reveals polymerisation exotherms with maxima at 190-260°C (ΔHp = 35-57 kJ/mol.) followed by embrittlement and shrinkage (when heated to 300°C). These phenomena may be due to the formation of poorly formed crystallites (activation energies span 155-380 kJ/mol) combined with thermal isomerisation.
  
  PubDate: 2013-05-03T09:37:08Z
Structure and biological evaluation of amino-functionalized PVP nanogels for fast cellular internalization
- Abstract: Publication date: Available online 30 April 2013
  Source:Reactive and Functional Polymers
  Author(s): C. Dispenza , S. Rigogliuso , N. Grimaldi , M.A. Sabatino , D. Bulone , M.L. Bondì , G. Ghersi
  Aminopropyl methacrylamide chloride-graft-poly(N-vinyl pyrrolidone) nanogels (NGs) were designed to exploit the favorable properties of poly(N-vinyl pyrrolidone) (PVP), such as its high affinity to water and complexation ability of ions, molecules and macromolecules, with the availability of primary amino groups for bioconjugation reactions. A thorough structural characterization of the nanoscalar networks was performed via 1H-NMR and solid state 13C-NMR spectroscopies, while solid state NMR relaxation time measurements completed the NGs description in terms of polymer network density. Information on the hydrodynamic size and surface charge densities were sought via dynamic light scattering (DLS) and ζ-potential measurements. These measurements, carried out both in water and in buffer and at the variance of pH, temperature and time, support the excellent colloidal stability of the amino-graft PVP nanogels and their redispersability from the dry physical form. The total absence of in-vitro toxicity and immunogenicity was ascertained first, and then cell localization studies in cell cultures of fluorescent variants were performed. Furthermore, the possibility of decorating the nanogels with bovine serum albumin (BSA) to obtain a stable bio-hybrid colloidal nanoconstruct was established. All the gathered evidences qualify these materials as potential candidates to be used as nanocarriers for intra-cellular delivery of protein and other biomolecular drugs.
  
  PubDate: 2013-05-03T09:37:08Z
Thiomer: A potential carrier for therapeutic delivery
- Abstract: Publication date: Available online 30 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Rakesh Kumar , V.R. Sinha
  The major challenge for any drug delivery system is the attainment of effective bioavailability without affecting the protective physiological mechanisms within the body. Systems based on mucoadhesive polymers have been widely preferred as these polymers not only prolong the residence time of the system on mucosal surfaces, but also retarded drug elimination. Mucin is one of the prominent targets to improve drug retention by enhancing adhesion between polymer and mucus membrane. Thiomers are modified mucoadhesive polymers that possess thiol bearing side chains display enhanced mucoadhesion that could be attributed to the formation of disulfide bonds between thiolated polymers and cysteine-rich subdomains of mucus glycoproteins. This review proposes the potential of thiomer as a promising and effective carrier for delivery of therapeutics.
  
  PubDate: 2013-05-03T09:37:08Z
Polymerization of β-cyclodextrin with 1,2,3,4-butanetetracarboxylic dianhydride: Synthesis, structural characterization, and bisphenol A adsorption capacity
- Abstract: Publication date: Available online 26 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Hiroyuki Kono , Taichi Nakamura
  Water-soluble and water-insoluble β-cyclodextrin polymers (β-CDPs) were prepared from β-CD using 1,2,3,4-butanetetracarboxylic dianhydride (BTCA) as a cross-linker. The structures of the synthesized water-soluble and water-insoluble β-CDPs were characterized in detail using FT-IR, solution- and solid-state NMR, and 1H diffusion-ordered spectroscopic techniques. The water solubility of β-CDP was dependent on the reaction temperature as well as the initial feed ratio of β-CD and BTCA. The BTCA content and the ratio of BTCA molecules cross-linked and grafted to β-CD were also found to influence the water solubility of the polymers. Insoluble β-CDPs were effective in adsorbing bisphenol A (BPA) from aqueous media, with this absorption being highest in materials of low BTCA content, which corresponds to material of high β-CD content per unit mass of β-CDP.
  
  PubDate: 2013-04-29T09:36:42Z
New Crosslinked-porous Poly-ammonium Microparticles as CO2 Adsorbents
- Abstract: Publication date: Available online 26 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Guangren Yu , Ziwei Man , Qingzeng Li , Na Li , Xinying Wu , Charles Asumana , Xiaochun Chen
  A new porous polymeric microparticle, poly[4-vinylbenzyltriethylammonium chloride] (P[VBTEA][Cl]), is prepared from the crosslinking polymerization of 4-vinylbenzyltriethylammonium chloride with N,N-methylenebisacrylamide via inverse suspension polymerization using cyclohexane as continuous phase, Span 80-Tween 80 as dispersant, and PEG600 as porogen. Two other microparticles, P[VBTEA][BF4] and P[VBTEA][PF6] are further obtained through ion-exchange. FT-IR, TGA, SEM, and EDS analyzes indicate that these microparticles have good porosity (apparent porosities are 55.0, 69.7 and 64.3%, respectively), high thermal stability, and large specific surface area, which make them potentially applicable as adsorbent agents. Their CO 2 adsorption-desorption performance is investigated. It is observed that such porous polymeric microparticles present high CO 2 sorption capability; typically, the CO 2 sorption of P[VBTEA][PF6] is 1.38wt% at 25°C and 1bar. Such porous polymeric microparticles are good candidates for CO 2 adsorption.
  
  PubDate: 2013-04-29T09:36:42Z
Synthesis and characterization of molecularly imprinted polymers with metallic zinc center for enrofloxacin recognition
- Abstract: Publication date: Available online 22 April 2013
  Source:Reactive and Functional Polymers
  Author(s): JJ. Recillas Mota , MJ. Bernad Bernad , J.A. Mayoral-Murillo , J. Gracia Mora
  A molecularly imprinted polymer with a metallic center (MIPc) was prepared and characterized. The template molecule for MIPc was a complex [Zn(Aza-f)(Enr)]NO3·H2O, Com, based on the ligands: enrofloxacin (Enr) and azabis(oxazoline) functionalized with styrene. Com was characterized before preparing MIPc. Moreover, the polymer prepared via non-covalent (MIPe) was prepared using Enr as the template molecule while no template molecules were used to prepare the non-imprinted polymer (NIP). MIPc was characterized using different spectroscopic techniques. In addition, the polymer molecular recognition capacity was studied by using rebinding kinetic studies. The kinetics shows that MIPc reach the equilibrium before the MIPe and NIP and the amount of Enr adsorbed is approximately 5 times higher that MIPe and NIP. Scatchard plots analysis for NIP, MIPe and MIPc shows Kd = 0.4768, 0.020, 0.0067 (mmolL-1) respectively. In comparison with the MIPe the binding affinity is nearly 100 times higher taking into account the high affinity sites. The selectivity of MIPc for Enr was higher than that for ofloxacin or flumequin, isotherms were fit to the Langmuir-Freundlich model, and the Enr showed a value of Ko = 21.38 mM-1, while the ofloxacin had a value of 2.2 x10-8 mM-1 and the flumequin of 1.6 x10-5 mM-1.
  
  PubDate: 2013-04-25T09:39:45Z
Coupling reaction with thiols as the efficient method of functionalization of ,,clickable’’ polylactide
- Abstract: Publication date: Available online 20 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Melania Bednarek
  The effectiveness of coupling reactions with thiols proceeding under different conditions is compared as the method of polylactide functionalization. Metal-free syntheses of polylactides (PLAs) fitted at one chain end with unsaturated (allyl, propargyl or acrylate) groups were performed by applying acid catalyzed activated monomer polymerization of lactide using allyl and propargyl alcohols or hydroxyethyl acrylate as initiators. Functional PLAs were used for thiol-ene and thiol-yne reactions proceeding according to radical as well as nucleophilic addition. The coupling efficiency for thiols containing carboxyl groups (in comparison with model benzyl thiol) was investigated by MALDI TOF method.
  
  PubDate: 2013-04-21T09:35:37Z
Homogeneous dispersion of SiO2 nanoparticles in an hydrosoluble polymeric network
- Abstract: Publication date: Available online 20 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Arnaud Zenerino , Sonia Amigoni , Elisabeth Taffin de Givenchy , Denis Josse , Frédéric Guittard
  The main difficulty still encountered in the elaboration of polymer/silica nanocomposites is the control of the nanoparticles dispersion homogeneity and the stability of the nanoparticle dispersion in the surrounding substance. The innovative point of this work is the elaboration of hybrid networks in aqueous solution performed with ASE (alkali swellable emulsion) thickeners grafted with silica nanoparticles. The thickening ability of the polymer should favour silica nanoparticles dispersion in fluid matrices. Two ASE copolymers were realised by copolymerisation in emulsion of MA (methacrylic acid) and EA (ethyl acrylate) and/or TFEM (trifluoroethyl methacrylate). The substitution of a part of EA by TFEM gave fluorinated ASE copolymers. Their free acid functions were then coupled with different ratio of amine functionalized silica nanoparticles to afford nanocomposites. The amounts of silica nanoparticles in the copolymers were determined by thermogravimetric experiments. Depending on the silica nanoparticles/copolymer ratio in basic aqueous solutions we achieved stable translucent gel like aqueous suspensions of silica nanoparticles containing 1 wt.% of the polymer/SiO2 nanocomposite.
  
  PubDate: 2013-04-21T09:35:37Z
Renewable antioxidant properties of suspensible chitosan-polypyrrole composites
- Abstract: Publication date: Available online 20 April 2013
  Source:Reactive and Functional Polymers
  Author(s): Rong-Jay Lee , Rauno Temmer , Tarmo Tamm , Alvo Aabloo , Rudolf Kiefer
  Conductive polymers have the ability to capture radicals and have become in focus for antioxidant applications of food packaging or biomedical applications. Unfortunately, the conducting polymers such as polypyrrole are difficult to suspense in solution after chemical or electrochemical polymerization. Chitosan, as a natural polymer from chitin, can be dissolved in diluted acetic acid solutions. In the present study, composites suspensible in diluted acetic acid solutions have been produced by the chemical polymerization of pyrrole in chitosan solution using ammonium persulfate (APS) as the oxidant. FTIR and UV-Vis measurements did identify an attachment of polypyrrole to chitosan. In order to optimize the activity and stability of the composites, the ratios of APS: polypyrrole: chitosan were analyzed. The chitosan-polypyrrole composites were formed as membranes (coatings); impedance measurements indicated their conductivity to be in the range of 10-3-10-7 Scm-1. The antioxidant (radical scavenger activity) properties were determined by the di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) assay. The radical scavenger activity of the composites was found renewable by means of electrochemical cycling.
  
  PubDate: 2013-04-21T09:35:37Z
Editors and Editorial Board
- Abstract: Publication date: May 2013
  Source:Reactive and Functional Polymers, Volume 73, Issue 5
  
  PubDate: 2013-04-17T09:39:51Z
Recent advances on ion-imprinted polymers
- Abstract: Publication date: Available online 6 April 2013
  Source:Reactive and Functional Polymers
  
  Selective recognition of metal ions is a real challenge for a large range of applications in the analytical field (from extraction to detection and quantification). For that purpose, ion-imprinted polymers (IIPs) have been increasingly developed during the last fifteen years on the principle of molecularly imprinted polymers (MIPs). Those imprinted materials are designed to mimic the binding sites of biological entities and assure an improved recognition of the template species. The aim of this review is to give the current state of the art in the conception of IIPs from the components to the polymerization process. Some applications of those materials will be also discussed.
  
  PubDate: 2013-04-09T09:34:29Z
Effect of the mimic structure on the molecular recognition properties of molecularly imprinted polymers for ochratoxin A prepared by a fragmental approach
- Abstract: Available online 2 April 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  In this work the fragmental approach was used to prepare several molecularly imprinted ethylene dimethacrylate-co-methacrylic acid polymers with molecular recognition towards the mycotoxin ochratoxin A, with the aim of searching for simpler mimic templates than the well-known N-(4-chloro-1-hydroxy-2-naphthoylamido)-(L)-phenylalanine. The screening for binding of two different kinds of ochratoxin-related molecules was performed by HPLC analysis. Ochratoxin A and the mimic templates were eluted in acetonitrile – acetic acid (0.1% v/v) and the imprinting factor was measured for all the ligands on all the columns packed with the imprinted polymers. The experimental results show that changes to the amino acidic sub-structure or the presence/absence of a chlorine atom in position 4 on the naphtalene ring system does not affect the molecular recognition of ochratoxin A by the resulting imprinted polymer. On the contrary, the presence of the bulky naphtalene ring system in the mimic template seems to be necessary to preserve the molecular recognition of ochratoxin. This binding behavior was found to be compatible with in silico simulations of the complexation between some of the mimic templates and molecules of methacrylic acid. The use of the mimic template N-(1-hydroxy-2-naphthoylamido)-(L)-phenylalanine seems to represent a synthetically simple approach to the preparation of imprinted polymers with molecular recognition properties towards ochratoxin A.
  
  PubDate: 2013-04-05T15:34:11Z
Novel Poly (3-hydroxyoctanoate)/ Poly (3-hydroxybutyrate) blends for Medical Applications
- Abstract: Available online 2 April 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Novel Poly(3-hydroxybutyrate)/Poly(3-hydroxyoctanoate) blends were developed with varying amounts of Poly(3-hydroxyoctanoate), P(3HO) and Poly(3-hydroxybutyrate), P(3HB) for their potential use in various medical applications. These blend films exhibited higher tensile strength and Young’s modulus values compared to neat P(3HO). The overall protein adsorption and% cell viability was also found to be significantly higher in the blend films than the neat P(3HO) film. Hydrolytic degradation was faster in the blend films and the degradation rate could potentially be tailored to achieve the optimum rate required for a particular medical application. Hence, these novel blends were found to be highly biocompatible with surface, mechanical and thermal properties suitable for a range of potential medical applications, a great step forward in the area of medical materials.
  
  PubDate: 2013-04-05T15:34:11Z
Enzymatic Hydrolysis of Polyester Based Coatings
- Abstract: Available online 2 April 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  The potential of two hydrolytic enzymes, namely a lipase from Thermomyces lanuginosus (TlL) and a cutinase from Humicola insolens (HiC) for hydrolysis of the phthalic acid backbone based polyester coatings was assessed. Two phthalic acid / trimethylolpropane based model substrates resembling the structure of the polyester backbone of coatings were synthesized. Out of both enzymes, only the cutinase was able to hydrolyze both model substrates while the larger substrate was hydrolyzed at a lower rate. The cutinase was also able to hydrolyze a coating (alkyd resin) both in suspension and as dried film. LC-MS analysis of the hydrolysis products released from the coating revealed the presence of oleic acid, its monoglyceride, phthalic acid and 2-((3-((2-((2,3-dihydroxypropoxy)carbonyl)benzoyl)oxy)-2-hydroxypropoxy)carbonyl)benzoic acid. These results indicate that the enzyme was able to hydrolyze the polyester backbone as well as to release fatty acid side chains. Consequently, enzymatic hydrolysis has a potential for the removal of coatings, their recycling or their functionalisation.
  
  PubDate: 2013-04-05T15:34:11Z
Chelidamic acid functionalized stimuli-responsive hydrogel supported-palladium catalyst for copper-free Sonogashira reaction in aqueous media
- Abstract: May 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers, Volume 73, Issue 5
  
  A thermo and pH-responsive hydrogel (PNIPAM-co-PPAP) was synthesized via free radical polymerization of N-isopropylacrylamide (NIPAM) and potassium 4-(acryloyloxy) pyridine-2, 6-dicarboxylate (PAP) in mixed solvents of water and tetrahydrofuran. SEM micrographs revealed that the hydrogel was macroporous and the pores within the matrixes were interconnected. The chelidamic acid functionalized PNIPAM-co-PPAP hydrogel exhibited excellent capacity to anchor palladium (II) and the resulting material showed well catalytic activity for copper-free Sonogashira reaction of aryl halides with phenylacetylene in aqueous media. The reactions proceeded well with 0.1mol% of Pd (II) catalyst, due to the good dispersion of Pd2+ in the macroporous structure as well as the enrichment of reactants within hydrogel under reaction conditions. Through the reversibly swelling/deswelling, the PNIPAM-co-PPAP hydrogel-immobilized Pd (II) catalyst could be easily recovered by simple method. Furthermore, the PNIPAM-co-PPAP /Pd catalyst exhibited good recyclability and could be recycled six times without remarkable loss in catalytic activity.
  
  PubDate: 2013-04-01T09:32:43Z
Synthesis and adsorption studies of novel hybrid mesoporous copolymer functionalized with protoporphyrin for batch and on-line solid-phase extraction of Cd2+ ions
- Abstract: Available online 29 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  A hybrid copolymer [poly(ethylene glycol dimethacrylate-protoporphyrin)-silica], synthesized by free radical copolymerization and sol-gel process was evaluated as novel adsorbent for solid-phase extraction of Cd2+ ions. Characterization of hybrid polymer was performed by FTIR, SEM and surface area analyzes. Adsorption isotherms built at pH 8.9 were very well adjusted (R2 = 0.9982) to hybrid non-linear Langmuir-Freundlich model for two sites, indicating the existence of different affinity constants for binding sites, which was confirmed by Scatchard plot. The estimated maximum adsorption capacity was found to be 8.28 mg g-1. The adsorption kinetics data also corroborated to the isotherm, where the Cd2+ ions adsorption followed the pseudo-second-order kinetic (R2 = 0.998). The on-line preconcentration procedure, optimized by means of factorial designs, was based on sample preconcentration (16 mL) at pH 8.9 through 50.0 mg of hybrid copolymer packed in mini-column at 8.0 mL min-1 flow rate. The on-line desorption of Cd2+ ions towards the FAAS detector was carried out in countercurrent at 5.0 mL min-1 flow rate using 0.8 mol L-1 HNO3. Using the on-line preconcentration procedure, the maximum adsorption capacity determined from breakthrough curve was found to be 2.25 mg g-1. Analytical curve ranged from 0.0 up to 50.0 g L-1 (r = 0.995), limit of detection of 0.27 g L-1, preconcentration factor of 38.4, sample throughput of 30 h-1 and consumptive index of 0.41 mL, were achieved. The preconcentration method, very tolerable to several foreign ions, was successfully applied to the Cd2+ ions determination in water samples and cigarette sample. The accuracy was checked from analysis of certified reference materials.
  
  PubDate: 2013-04-01T09:32:43Z
In situ Growth of CdS Nanocrystal Arrays by Self-Assembling Microporous Templates from Dendritic-Linear PGMA-HPAM-r-PS Copolymers
- Abstract: Available online 30 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  A novel in-situ chemical precipitation method to directly synthesize CdS nanocrystal arrays in the presence of microporous templates of poly(glycidyl methacrylate-grafted-3,3’-dimethyl-(4-hydroxyphenylazanediyl) bis(2-methylpropanoate)) -random-polystyrene (PGHS), which were formed by self-assembling dendritic-linear PGHS copolymers via the solvent-induced phase separation process, were investigated. The surface morphology of the PGHS template and the spatial positions of the CdS nanocrystals in the PGHS-CdS could be easily and quickly controlled by altering the content of the dendritic GMA-HPAM segments. The diameters of the CdS nanocrystals on the PGHS-CdS template were uniform in the range of 3-4 nm. Large-area, hexagonally ordered CdS nanocrystal-array domains were discovered in the PGHS2-CdS template used in this study.
  
  PubDate: 2013-04-01T09:32:43Z
Synthesis, characterization and third-order nonlinear optical properties of novel hyperbranched donor-acceptor polyfluorenes based on 1,3,6,8-tertsubstituted carbazole core
- Abstract: Available online 26 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Two novel hyperbranched donor-acceptor polyfluorenes based on 1,3,6,8-tertsubstitued cabazole core (4BrCzP1 and 4BrCzP2) were synthesized and characterized. The third order nonlinear optical properties of the materials were studied using z-scan technique with femtosecond Ti: sapphire laser with delivering pulses of 140fs at 800nm. The nonlinear optical refractive index was 9.29×10-8esu for 4BrCzP1 and 3.19×10-7esu for 4BrCzP2, respectively. While the third order nonlinear susceptibility was 1.29×10-9esu for 4BrCzP1 and 4.33×10-9esu for 4BrCzP2, respectively. The experimental results indicated that the hyperbranched polyfluorenes was a promising candidate in the application of third order nonlinear optical materials.
  
  PubDate: 2013-03-28T10:33:33Z
Clickable, Versatile Poly(2,5-dithienylpyrrole) Derivatives
- Abstract: Available online 26 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  In this study a novel, clickable, azide containing conducting polymers based on 1-(2-azido-ethyl)-2,5-dithiophene-2-yl-1H-pyrrole (SNS-N3) were synthesized and characterized. Optical and electronic properties of homopolymer (PSNS-N3) were investigated and colorimetric studies were performed. The homopolymer has a band gap of 2.49 eV and it displays yellow to blue coloration upon doping. Electrochemically prepared copolymers of SNS-N3 and 3,4-ethylenedioxythiophene (EDOT) formed multichromic, color tunable electrochromic materials with continuous color gradient from cinnamon, mustard, lime green, blue and dark blue. Spectroelectrochemical analyses revealed that the neutral copolymers possess two absorption maxima (∼320 and 450 nm) where the relative intensity and position of the two depends on polymerization potential. Copolymer films could be fully switched between their neutral and oxidized forms in ∼ 1.2 s with a percent transmittance of ∼ 65% at 950 nm. Moreover, a PSNS-N3 coated ITO electrode was subjected to click reaction using ethynylferrocene. CV and FTIR studies revealed that ferrocene could easily be attached onto the electrode surface without loss of electroactivity of both ferrocene and PSNS backbone. Our results suggest that electrochemically prepared PSNS-N3 films offer a novel and multipurpose platform for simple, effective post-functionalization of poly(2,5-dithienylpyrrole)s under mild conditions.
  
  PubDate: 2013-03-28T10:33:33Z
Zn2+ - imprinted porous polymer beads: Synthesis, structure, and selective adsorption behavior for template ion
- Abstract: Available online 26 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Zn2+-imprinted polymer was synthesized in porous spherical forms via a self-assembled complex between 2,2’-bipyridyl/4-vinylpyridine complexant/functional monomer and Zn2+ template ion. Diameters of particles ranged from 250 to 550 μm to enlarge the surface area and thus enhance the adsorption capacity. The presence/absence of the template ion in the preparation of the imprinted polymer was confirmed by EDX spectroscopy, and the physical structure of the particles was investigated using ESEM and BET analysis. The particle and the pore size were controlled by the cross-linker/monomer feed ratio. The adsorption capacity of the imprinted polymers was 210.61 μmol g-1 for Zn2+, while those for Cu2+, Ni2+, and Pb2+, were 37.92 μmol g-1, 33.02 μmol g-1, and 9.70 μmol g-1, respectively. This big discrepancy of the adsorption capacities illustrates the excellent separation selectivity of the imprinted polymers. The adsorption capacity decreased significantly at pH below 4.5, as the polymers are easily protonated. The imprinted particles lost only 10% of their adsorption ability after 10 repeated uses.
  
  PubDate: 2013-03-28T10:33:33Z
A novel cross-linked polyzwitterion/anion having pH-responsive carboxylate and sulfonate groups for the removal of Sr2+ from aqueous solution at low concentrations
- Abstract: Available online 26 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  A novel cross-linked polyzwitterion (CPZ) was synthesized via cycloterpolymerization of N,N-diallyl-N-sulfopropylammonioethanoic acid (92.5 mol%), a cross-linker 1,1,4,4-tetraallylpiperazinium dichloride (7.5 mol%), and sulfur dioxide (100 mol%) in the presence of azoisobutyronitrile in dimethylsulfoxide at 60 oC. CPZ, upon treatment with NaOH, was converted into a cross-linked polyzwitterion/anion (CPZA). The experimental data for the adsorption of Sr2+ on CPZA fitted the pseudo-second-order kinetic model and Freundlich as well as Temkin isotherm models. The adsorption process was spontaneous and exothermic in nature with negative values for both ΔG and ΔH. The low activation energy of 7.18 kJ/mol indicated the adsorption as a favourable process. The removal for the initial concentrations of 200 ppb and 1000 ppb (i.e., 1 ppm) of Sr2+ ions was observed to be 87 and 92%, respectively. An efficient synthetic access to the resin and excellent adsorption capacity and desorption would enable its use in the treatment of radioactive nuclear waste containing Sr2+ ions. The CPZA provided an opportunity to test the efficacy of a zwiiterionic/anionic group in the removal of Sr2+ ions in low concentrations.
  
  PubDate: 2013-03-28T10:33:33Z
Suprarmolecular Hydrogels Driven by the Dual Host-guest Interactions between α-Cyclodextrin and Ferrocene-Modified Poly (ethylene glycol) with Low-Molecular-Weight
- Abstract: Available online 21 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  In general, α-cyclodextrin (α-CD) and low-molecular weight poly (ethylene glycol) (low-MW PEG) (Mw=400-10000) can not construct supramolecular hydrogels but easily form crystalline precipitates. In this study, low-MW PEG (Mn=2000, PEG-2000) was functionalized by ferrocene as mono-end-group. The obtained ferrocene- modified PEG-2000 (FcPEG-2000) further self-assembled into supramolecular hydrogel with α-CD even at low concentration (C FcPEG-2000=17mg/ml), driven by dual host-guest interaction between α-CD and FcPEG-2000. Interestingly, the hydrogel was still observed even when hydrophobic Fc group was oxidized to hydrophilic ferrocenium (Fc+) or included into the cavity of β-CD. In the former case, the existence of Fc+ end groups is considered to decrease the probability of PEG de-penetration from α-CD cavity, so that α-CDs have more location and opportunities to aggregate into more channel-type crystalline domains as physical cross-linking points. While in the later case, the synergistic effect of host-guest interaction between β-CD and ferrocenyl groups and host-guest interaction between α-CD and PEG chains are considered to be the main reason. The resultant FcPEG-2000 based hydrogels showed the property of shear-thinning.
  
  PubDate: 2013-03-24T10:46:24Z
Cytocompatible polyurethanes from fatty acids through covalent immobilization of collagen
- Abstract: May 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers, Volume 73, Issue 5
  
  Two different polyurethanes synthesized from two triols derived from undecenoic acid (PU1) and oleic acid (PU2) fatty acids were functionalised with Collagen type I via plasma treatment aimed at obtaining novel biomaterials with improved biological properties. Scanning Electron Microscopy, X-ray photoelectron spectroscopy, optical microscopy, colorimetric titration methods and contact angle measurements confirmed the surface changes at each stage of treatment, both in terms of morphology and chemical composition. The results for osteoblastic cells (MG63) cultured in vitro proved that PUs modified with collagen had better cytocompatibility that the control PUs. In particular, PU2 displays higher cytocompatibility.
  
  PubDate: 2013-03-24T10:46:24Z
Immunoglobulin G recognition with Fab fragments imprinted monolithic cryogels: Evaluation of the effects of metal-ion assisted-coordination of template molecule
- Abstract: Available online 23 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  In this study, we applied the epitope imprinting approach to prepare molecularly imprinted monolithic cryogels for immunoglobulin G (IgG) recognition. In this respect, we imprinted Fab fragments of IgG molecules instead of intact protein molecules via two different non-covalent interactions. In the first approach, we directly coordinated Fab fragments with N-methacryloyl-L-histidine (MAH), polymerizable derivative of L-histidine, but for the second, we used cupric ions [Cu(II)] as mediator between MAH and Fab fragments. The monolithic cryogels were characterized by Fourier transform infrared (FTIR) spectroscopy, swelling test, and scanning electron microscopy. Then, the monolithic cryogels were used for Fab fragment adsorption from aqueous solution while evaluating the factors such as pH and Fab fragment concentration affecting on adsorption process in continuous set-up. After that, monolithic cryogels were used for IgG adsorption by varying pH, IgG concentration, flowrate, and temperature in appropriate ranges. Maximum IgG adsorption capacities were determined as 32.4 mg/g and 49.0 mg/g for directly coordinated cryogel (MIPDirect) and Cu(II) assisted cryogel (MIPCu(II) assisted), respectively. Non-imprinted monolithic cryogels were also prepared for control purposes. In addition to Fab fragments and IgG molecules, albumin and Fc fragment of IgG molecules were used as competitor biomolecules in order to investigate the selectivity gained by imprinting process. Relative selectivity constants were calculated as 1.47, 2.64 and 3.89 for MIPDirect and 2.90, 8.98, and 11.51 for MIPCu(II) assisted for Fab/IgG, Fab/Fc, and Fab/albumin as biomolecule pairs, respectively. The desorption efficiency and reusability of MIPCu(II) assisted cryogel were better than that of MIPDirect. The results reported here showed that the metal ion assistance improved the selectivity features of the imprinted cryogels and allowed to study under milder conditions with enhanced adsorptive properties.
  
  PubDate: 2013-03-24T10:46:24Z
Polysiloxane - POSS systems as precursors to SiCO ceramics
- Abstract: Available online 16 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  In the work, two linear polysiloxanes (D2V and V3 polymers) containing vinyl (Vi) groups regularly distributed along their chains were cross-linked by hydrosilylation with Si-H groups containing polyhedral oligomeric silsesquioxane (POSS) molecules, namely: dimethylsiloxy-substituted octahedral oligosilsesquioxane (Q8MH 8). The reactions were carried out at equimolar Si-Vi: Si-H groups ratios in methylene chloride, tetrahydrofuran and toluene in order find out the optimum solvent for achieving the highest possible polymer cross-linking levels. In toluene, cross-linking was also performed at lower reactive groups molar ratios. Investigation of the cross-linked systems allowed establishing that hydrosilylation in toluene was the most efficient. Independently of the Si-Vi: Si-H groups molar ratio in the starting reaction medium, D2V polymer reacted with Q8MH 8 to a higher extent than the V3 one. In some systems, Q8MH 8 acted not only as a cross-linker, but also as filler. Pyrolysis of the cross-linked polymers conducted in Ar atmosphere led to formation of SiCO ceramics with high yields (63.4-85.1 wt.%). Particularly advantageous effect of incorporation of POSS molecules on ceramic yield was observed for the D2V polymer. SiCO materials obtained are pore- and crack-free and can be applied as chemically and thermally stable protective layers on various substrates.
  
  PubDate: 2013-03-20T10:34:48Z
Editors and Editorial Board
- Abstract: April 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers, Volume 73, Issue 4
  
  PubDate: 2013-03-20T10:34:48Z
Impedimetric detection of dopamine on poly(3-aminophenylboronic acid) modified skeleton nickel electrodes
- Abstract: Available online 16 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Detection of biologic compounds in particular dopamine is usually based on the complexation between boronic acid groups and diols. For this reason the development of new sensors based on direct monitoring of boronic acid - diol complexation is attractive. A measurable electric response due to a change in the dopamine concentration can be achieved on electrodes modified with boronic groups. In this work a modified electrode has been obtained by electropolymerization of 3-aminophenylboronic acid in aqueous solutions on a preformed polyaniline layer electrochemically deposited on smooth and skeleton nickel electrodes. The modified electrodes have been tested as impedimetric sensors for the detection of dopamine in aqueous phosphate buffer at pH = 7.4. Both sensors gave a linear response for dopamine concentrations between 10-5 and 10-10 mol L-1. Poly(3-aminophenylboronic acid) modified skeleton nickel electrode has the advantage of an increased specific surface area, that lead to a high density of boronic acid groups and hence to a better sensitivity.
  
  PubDate: 2013-03-20T10:34:48Z
Hydration of ion exchangers: Thermodynamics and quantum chemistry calculations
- Abstract: Available online 14 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Comparative studies of the state of water molecules in carboxylic acid resins were carried out using classic thermodynamics and ab initio quantum chemical calculation of the structure of representative fragments of their polymeric matrix in the presence of different amounts of water molecules. Water sorption isotherms were obtained for H+, Li+, Na+, K+ Mg2+, Ca2+ and Ba2+ forms of the carboxylic acid ion exchanger Lewatit S8227 using the isopiestic method. Quantum chemistry calculations were performed by the Firefly QC package, which is partially based on the GAMESS (US) source code, on the theory level RHF/MINI. Atomic structures of fragments of the resin interior containing 1 - 6 monomeric residues and 0 - 10 water molecules per functional group were computed. It has been shown that the water sorption isotherms are well described by the previously derived equation on the assumption of the presence in the swollen ion exchanger of one or two formal hydrates. Quantum chemistry calculations allow independent evaluation of the number of water molecules in the hydrates and in so doing reduce the number of fitting parameters needed for quantitative description of the water sorption isotherms. They also allow classifying the water molecules in the resin according to the type of interaction with fixed ion – counter-ion ion pair.
  
  PubDate: 2013-03-16T10:35:10Z
Sorption mechanism of copper in chitosan hydrogel
- Abstract: Available online 14 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Sorption mechanism of copper for spherical hydrogel structures formed by the phase inversion method are determined. Based on equilibrium and the research of structural attempt was made to explain the mechanism of sorption. Equilibria was describe by Langmuir, Langmuir- Freundlich, equation. The chemical character of sorption was confirmed by IR and WAXS and XPS spectra.
  
  PubDate: 2013-03-16T10:35:10Z
High Molecular Weight Copolymers of Vinylferrocene and 3-Phenyl[5]ferrocenophane-1,5-dimethylene with Various N-Substituted Maleimides
- Abstract: Available online 14 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Two series of ferrocene-containing polymers have been synthesized from various N-substituted maleimides with 3-phenyl[5]ferrocenophane-1,5-dimethylene (3A-C) or vinylferrocene (4A-C). These copolymers exhibit high molecular weights and 4A-C formed free standing films. Electrochemical studies with copolymers 3A-C and 4A-C in dimethylacetamide show chemical reversibility for all of the materials but only copolymers 4A-C show electrochemical reversibility. These copolymers were also electrochemically deposited from methylene chloride on to a platinum electrode to form chemically modified electrodes (CMEs). The CMEs show desorption of the ferrocene polymers in acetonitrile solutions but exhibited good stability in aqueous solution. The thermal stabilities of the copolymers 4A-C are typical for a ferrocene containing polymer with 10% weight loss occurring at ca. 385°C. Copolymers 3A-C exhibit higher thermal stabilities with 10% weight loss at 438°C. Differential scanning calorimetry measurements of the copolymers showed melt transitions just before the onset of thermal decomposition.
  Graphical abstract
  
  PubDate: 2013-03-16T10:35:10Z
Synthesis of polyguanamines from 2-N,N-dibutylamino-4,6-dichloro-1,3,5-triazine with aromatic diamines
- Abstract: Available online 15 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Solution polycondensation of 2-N,N-dibutylamino-4,6-dichloro-1,3,5-triazine (BDCT) with various aromatic diamines, including 4,4′-oxydianiline (ODA), p-phenylenediamine (pPDA), m-phenylenediamine (mPDA), o-tolidine (oTD), 4,4′-(9-fluorenylidene)dianiline (BAFL), and 2,4-diamino-6-(N,N-dibutylamino)-1,3,5-triazine (DABT), was investigated. High molecular weight (>10,000) polyguanamines (PG)s were obtained via the polymerization of BDCT with ODA, pPDA, oTD, and BAFL at 150–180 °C in N-methylpyrrolidone (NMP) for 6 h. The polymerizability with BDCT was determined on the basis of the molecular weights of the polymers and the chemical shifts of the NMR data as follows: ODA > oTD > BAFL > pPDA > mPDA >> DABT. PGs were obtained from the reaction of BDCT with ODA and mPDA in only 55–77% yield, which may be attributed to the formation of cyclic oligomers. All of the polymers showed high thermostability (5% weight-loss temperature in N2 greater than 444 °C), and the polymers generated from reaction of BDCT with ODA, mPDA, and BAFL exhibited good solubility in tetrahydrofuran and polar aprotic solvents such as NMP.
  
  PubDate: 2013-03-16T10:35:10Z
Environmentally friendly PBS-based copolyesters containing PEG-like subunit: effect of block length on solid-state properties and enzymatic degradation
- Abstract: Available online 15 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  The use of biodegradable polymers could contribute to mitigate the huge environmental problems caused by the massive use of conventional non biodegradable plastics, especially in the case of time-limited applications. In this framework, in the present study we propose a new class of multiblock eco-friendly copolyesters containing butylene succinate (BS) and triethylene succinate (TES) sequences. In particular, four copolyesters with the same chemical composition but different block lengths – P(BS10TES10), P(BS5TES5), P(BS3TES3), and P(BS2TES2) – were synthesized by reactive blending. For sake of comparison, homopolymer PBS was also considered. Physicochemical characterization (DSC, WAXS, tensile tests, WCA) of the copolymers synthesized demonstrated that it is possible to control polymer crystallinity, thermal and mechanical properties and wettability of the final product by simply varying block length. As a matter of fact, melting point, crystallinity degree, elastic modulus and surface wettability decreased with the block length; on the contrary, elongation to break significantly increased. Enzymatic hydrolysis performed with lipase from Candida cylindracea ([E]=50 U/ml, T=30°C and pH=7.0), showed that copolymers biodegradation is much higher than that of PBS homopolymer. Moreover, copolymers displayed a tunable range of degradation rates, related to their crystallinity degree and hydrophilic/hydrophobic ratio, which render them promising for different time-span applications, ranging from long-term (P(BS10TES10) to very short-term (P(BS2TES2)).
  
  PubDate: 2013-03-16T10:35:10Z
Preparation of UV-curable functionalized graphene/polyurethane acrylate nanocomposite with enhanced thermal and mechanical behaviors
- Abstract: Available online 15 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Functionalized graphene nanosheets (f-GNS) were synthesized by a simple covalent functionalization of graphene with 3-methacryloxypropyl trimethoxysilane (MPTES). The results from FTIR, XPS and XRD showed that MPTES was successfully attached onto the surface of graphene. Functionalized graphene/polyurethane acrylate (f-GNS/PUA) nanocomposites were prepared by UV radiation of PUA with f-GNS. The onset thermal degradation temperature of f-GNS/PUA nanocomposite was increased by 16 °C, at an f-GNS content of 1 wt%. Meanwhile, the storage modulus and glass transition temperature of the nanocomposites were enhanced by incorporating f-GNS into the PUA. This is believed to be attributed to that the covalent functionalization of graphene can improve both the dispersion of f-GNSs in the polymer matrix and the interfacial interactions between f-GNSs and PUA.
  
  PubDate: 2013-03-16T10:35:10Z
Synthesis, Characterization, and Properties of novel hydrophobically associating fluorinated copolymers for DNA delivery
- Abstract: Available online 4 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Novel fluorinated associative copolymers poly(ethylene glycol)-b-poly(2-(perfluorohexyl)ethyl methacrylate (PFHEMA)-co-3-[N-(2-methacroyloylethyl)-N,N-dimethylammonio]-propane sulfonate (DMAPS)) (PEG-b-PPFHEMA/PDMAPS) were prepared as a type of non-viral gene vector. The series of PEG-b-PFHEMA/DMAPS with different molecular weights and compositions were characterized by gel permeation chromatography–multi-angle light scattering, 1H NMR, 19F NMR, and elemental analysis. The interactions of the copolymers with calf thymus DNA and the morphologies of the resulting complexes were studied by fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. In addition, the DNA–polymer interaction, as determined by the gel retardation assay, and the low cytotoxicity of PEG-b-PPFHEMA/PDMAPS demonstrated that these copolymers have good DNA binding capacity and potential for high performance in the practical application of DNA delivery.
  
  PubDate: 2013-03-08T10:35:21Z
Promoted cell proliferation and mechanical relaxation of nanocomposite hydrogels prepared in cell culture medium
- Abstract: Available online 5 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Nanocomposite hydrogels (NC gel) were synthesized through in-situ polymerization of N-isopropylacrylamide (NIPAm) in the hectorite clay suspension made from cell culture medium Dulbecco’s modified Eagle medium (DMEM). Cell cultured on these NC gels (D-NC gel) surface proliferated faster compared with that on the NC gels synthesized in water due to the nutrients in the D-NC gels. Cells attached and proliferated faster on the D-NC gels with higher modulus. In addition, cell sheets with good viability spontaneously detached from the gel surface by lowering temperature. Their tensile elongation at break was higher than 7 and the true strength σtrue was up to 800 kPa. The stress-strain curves of the D-NC gels were described quantitatively with the Mooney-Rivlin equation. A stretched exponential stress equation was adopted to express the stress relaxation of the D-NC gels with an average relaxation time τ (∼102 s) estimated from data fitting, showing a broad distribution (polydispersity k ∼ 0.4). The τ value, which was used in simulation for the tensile creep compliance of the D-NC gels, became shorter with increasing clay concentration due to the decrease in the network chain length. The relaxation process was similar to the natural articular cartilage. This work provides a facile way to produce hydrogels with improved cell compatibility and satisfactory mechanical properties for biomedical applications.
  
  PubDate: 2013-03-08T10:35:21Z
PMMA Thermoreversible Networks by Diels-Alder reaction
- Abstract: Available online 7 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  Reversibly crosslinked polymethylmethacrylate were prepared by Diels-Alder (DA) reaction using multi-furan and multi-imide precursors. Furan functionalized PMMA were obtained by reactive extrusion (transesterification) between a commercial PMMA and furfuryl alcohol using tin(II)2-ethylhexanoate (Sn(oct)2) or 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) catalysts. Maleimide based coupling agents were prepared by amine-anhydride reaction. Thermomechanical properties of the PMMA precursors and issued networks were analyzed. Two G’ and G” cross-over temperatures were obtained during the heating and cooling cycles. The first one at 110°C can be assimilated to physical gel formation and the second one at 160°C to its breaking. When the network was formed, an increasing of these temperatures is observed. Also, the G’ between these temperatures increased with the network density. The obtained network had a shape memory behavior.
  
  PubDate: 2013-03-08T10:35:21Z
A Novel Electron Beam-Based Method for the Immobilization of Trypsin on Poly(ethersulfone) and Poly(vinylidene fluoride) Membranes
- Abstract: Available online 4 March 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers
  
  A novel technique for the covalent immobilization of trypsin in an one-step reaction using low-energy electron beam is described. The enzyme immobilization was applied on poly(ethersulfone) and poly(vinylidene fluoride) microfiltration membranes. For this purpose, the membranes were dipped in an aqueous solution of trypsin followed by electron beam treatment. The effect of irradiation conditions on the immobilization was investigated, as well as the resulting membrane properties with respect to enzymatic activity, immobilized enzyme concentration, pure water flux, scanning electron microscopy, and porosimetry. This technique shall provide a simple, inexpensive method for enzyme immobilization on various polymer membranes and offer a tool for the application in enzymatic membrane reactors.
  
  PubDate: 2013-03-08T10:35:21Z
Lightly branched comb polyesters: Application in fast drying solvent-borne coating formulations
- Abstract: April 2013
  Publication year: 2013
  Source:Reactive and Functional Polymers, Volume 73, Issue 4
  
  Novel oxazoline-based comb-polymers possessing linoleyl or oleic side chains have been synthesized and used to produce low viscosity coatings. Inclusion of the polymers in model paint formulations results in coatings that exhibit faster drying times than commercially available alkyd resin formulations. The comb polymers were produced from diol substituted oxazoline monomers that were synthesized through a scalable, solvent free protocol and purified by simple recrystallisation. Co-polymerisation of the oxazolines with adipic acid at 160°C in the bulk resulted in the targeted polyester comb type polymers. The polymers were soluble in a range of organic solvents and compatible with commercial alkyd resins. Model paint formulations containing up to 40wt% of the linoleyl-based comb polymers exhibited a dramatic reduction in viscosity (from 35 to 13 Poise at 25°C) with increasing quantities of polymer added. Dynamic mechanical analysis (DMA) studies revealed that the drying rate of the model paint formulations containing the comb polymers was enhanced when compared with that of commercial alkyd resins.
  
  PubDate: 2013-02-28T09:03:43Z